1. Field of the Invention
The invention relates to an antenna apparatus, and particularly relates to an antenna apparatus for improving a radiation pattern.
2. Description of Related Art
With the development of communication technology, the application of wireless communication technology in electronic products increases day by day, which results in the diversification of communication products. For example, cell phones, personal digital assistants (PDAs) with wireless network capability, and the global positioning system (GPS) are all related to wireless communication. In recent years, since consumers have more demands regarding the functions of communication products, communication products with various functions and designs have been developed, and computer network products with wireless communication capability have become more popular recently.
As for wireless communication products, the most crucial point is the design of an antenna, because the design quality of the antenna tends to influence the quality of communication. Generally, antennas include internal antennas and external antennas. External antennas include monopole antennas, dipole antennas and helix antennas. Internal antennas include planar inverted F antennas (PIFA) and microstrip antennas. The planar inverted F antennas are widely used in communication products.
The conventional wireless communication techniques mainly use patch antennas to generate a broadside radiation patterns. However, due to the space required by a patch antenna, patch antennas may not be applicable in miniatured communication products. As a result, the conventional way of handling this issue is to use the planar inverted F antennas to reduce the space taken by the antenna. However, the radiation patterns of the planar inverted F antennas are prone to be influenced by the components disposed around, so the distribution of the radiation patterns of the planar inverted F antennas is limited.